I also do photometry (asteroids and more) with the old SBIG ST-10.
No problem with other software just with SGP when using last SBIG drivers thru SBIG Driver Checker 64 Application.
Problems I had are very similar to yours, sometimes various error message, sometimes ok for 1 image but problem with the next one and only with SGP. A insisted because SGP is a very good software to schedule a full night, so, after many trials arrived to the page of Diffraction Limited that deal with this specific problem of ST/STL camera and SGP.
I downloaded the driver and with it you have a README.txt that explain how to use it, very simple.
I use it on W7 pro and W10 portable computers with various setup (USB hub, more or less equipment) and that solved the error message almost all the time (not always)
Buy the way its close to sunset time for me, no clouds, so its time to wake up the setup.